The march is being promoted as a day of atonement for black men, a time to unify them, a time for them to rededicate themselves to their families.

Even without Simpson in the mix, the planned march has been controversial, largely because one of its chief organizers is Nation of Islam leader Louis Farrakhan.

Simpson was not explicitly invited to the event. But he and Cochran "would be more than welcome," Abdul Allah Muhammad, an assistant to Farrakhan and the event's director of registration, said on Monday.

"It's for a million black men," Muhammad said. "And there's no reason for us to exclude them, no reason for us not to welcome them with open arms."

But he said he did not know for sure whether Simpson and Cochran would attend the march. "That's a rumor to us just like it is to you," he said.

Organizers are hoping the march, a mix of prayer and protest, will draw at least a million black men to the Mall. That would be about four times the number of people who attended Martin Luther King Jr.'s "I Have a Dream" speech in Washington in 1963.

At least one national poll finds that an overwhelming majority of blacks say they support such a march. About 84 percent of blacks surveyed who have heard about the march think it's a good idea, the Washington Post-ABC News poll found.

The survey found that most blacks draw a "clear distinction" between the march and its two main organizers, Farrakhan and former NAACP Executive Director Benjamin Chavis, the Post reported. Farrakhan has been accused of maligning Jews, Catholics, Christian ministers and others. Chavis was fired from his NAACP post after using organization money to settle a sexual harassment case.

Simpson may show up, but another black celebrity has said he can't make it. On Monday, retired Army Gen. Colin Powell turned down Farrakhan's invitation to speak at the event, saying he could not appear because of commitments to promote his autobiography, My American Journey.